System for reducing aerodynamic drag forces on a trailer

ABSTRACT

A system for reducing drag on a trailer includes a flexible membrane including a perimeter coupled to a rear end of the trailer. A variable-volume cavity is defined between the flexible membrane and the rear end. The system also includes a source of pressurized gas coupled to the trailer and in fluidic communication with the variable-volume cavity, and a controller operable to control a flow of the pressurized gas from the source to the variable-volume cavity such that the flexible membrane is moved from a stowed profile, wherein the flexible membrane is collapsed against the rear end of the trailer, to a first deployed profile, wherein the flexible membrane is maintained in a first pre-selected tapered aerodynamic shape projecting rearward from the rear end.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to, PCTPatent Application Serial No. PCT/US2021/014192 filed Jan. 20, 2021 forSYSTEM FOR REDUCING AERODYNAMIC DRAG FORCES ON A TRAILER, which is acontinuation of, and claims priority to, U.S. patent application Ser.No. 16/750,738 filed Jan. 23, 2020 for SYSTEM FOR REDUCING AERODYNAMICDRAG FORCES ON A TRAILER, the disclosures of all of which are herebyincorporated by reference in their entirety.

BACKGROUND

The field of the disclosure relates generally to systems for reducingaerodynamic drag forces on a trailer, and more particularly, to aflexible membrane that is actively deployable to create a pre-selectedtapered aerodynamic shape, projecting rearward from the rear of thetrailer, to alter an aerodynamic profile of the trailer.

Fuel usage is a major driver of transport costs and also has anenvironmental impact. At least some known vehicles used fortransportation, such as tractor trailers, include blunt-shaped rearsurface profiles that tend to induce vortices in air traveling aroundand past the vehicle. These vortices create aerodynamic drag forces onthe vehicle that reduce fuel efficiency, and therefore increasetransport costs and environmental impacts.

Some known systems attempt to reduce aerodynamic drag by altering therear profile of the vehicle through the use of fixed or selectivelydeployable rigid panels at the rear of the vehicle. However, because ashape of the panels is fixed, such systems have limited, if any,capability to adjust to different operating conditions (e.g., differentspeeds, different cross-winds) that may be encountered by the vehicle.Accordingly, drag reduction is at best sub-optimal during substantialperiods of operation of the vehicle.

Other known systems attempt to reduce aerodynamic drag by altering therear profile of the vehicle through the use of a flexible air bagdeployable at the rear of the vehicle. Air captured at the front orsides of the vehicle at speed is routed into the bag to inflate the bag.However, because a shape of the bag is determined by an air flow andpressure essentially fixed by the speed of the vehicle, such systemsagain have limited capability to adjust to different operatingconditions.

Accordingly, a system that is capable of actively changing the rearprofile of the vehicle among a number of different shapes, actuated in afashion that is independent of vehicle speed, would find utility.

BRIEF DESCRIPTION

In one aspect, a system for reducing drag on a trailer provided. Thesystem includes a flexible membrane including a perimeter coupled to arear end of the trailer. A variable-volume cavity is defined between theflexible membrane and the rear end. The system also includes a source ofpressurized gas coupled to the trailer and in fluidic communication withthe variable-volume cavity, and a controller operable to control a flowof the pressurized gas from the source to the variable-volume cavitysuch that the flexible membrane is moved from a stowed profile, whereinthe flexible membrane is collapsed against the rear end of the trailer,to a first deployed profile, wherein the flexible membrane is maintainedin a first pre-selected tapered aerodynamic shape projecting rearwardfrom the rear end.

In another aspect, a system for reducing drag on a trailer is provided.The system includes a plurality of flexible membranes each including arespective perimeter coupled to a rear end of the trailer. A respectivevariable-volume cavity is defined between each flexible membrane and therear end. The system also includes at least one source of pressurizedgas coupled to the trailer and in fluidic communication with therespective variable-volume cavity defined by each flexible membrane. Thesystem also includes a controller operable to control a flow of thepressurized gas from the at least one source to the respectivevariable-volume cavity defined by each flexible membrane, such that theplurality of flexible membranes is movable between a first deployedprofile, wherein the plurality of flexible membranes cooperate tomaintain a first pre-selected tapered aerodynamic shape projectingrearward from the rear end of the trailer, and a second deployedprofile, wherein the plurality of flexible membranes cooperate tomaintain a second pre-selected tapered aerodynamic shape projectingrearward from the rear end. The second pre-selected tapered aerodynamicshape is different from the first pre-selected tapered aerodynamicshape.

In another aspect, a system for reducing drag on a trailer is provided.The system includes a flexible membrane including a perimeter coupled toa rear end of the trailer. A variable-volume cavity is defined betweenthe flexible membrane and the rear end. The system also includes atelescoping actuator coupled to the rear end and including a distal end.The distal end is selectively movable, within the variable-volumecavity, between a retracted position, wherein the distal end isproximate to the rear end, and a first extended position, wherein thedistal end is spaced apart from the rear end at a first distance. Thesystem also includes a source of pressurized gas coupled to the trailerand in fluidic communication with the variable-volume cavity, and acontroller operable to control a flow of the pressurized gas from thesource to the variable-volume cavity. The controller and the telescopingactuator are cooperatively operable to move the flexible membrane from astowed profile, wherein the telescoping actuator is in the retractedposition and the flexible membrane is collapsed against the rear end ofthe trailer, to a first deployed profile, wherein the telescopingactuator is in the first extended position and the flexible membrane ismaintained in a first pre-selected tapered aerodynamic shape projectingrearward from the rear end.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a vehicle including a flexiblemembrane deployment system in a deployed profile;

FIG. 2 is a schematic sectional elevation view of a plurality ofdeployed profiles of the flexible membrane deployment system of FIG. 1;

FIG. 3 is a schematic bottom view of a rear portion of the vehicle ofFIG. 1 including the flexible membrane deployment system in a collapsedprofile;

FIG. 4A is a schematic perspective view of the vehicle of FIG. 1including the flexible membrane deployment system in a vehicle-unloadingconfiguration;

FIG. 4B is a schematic perspective view of the rear portion of thevehicle of FIG. 1 including the flexible membrane deployment system inthe vehicle-unloading configuration and a rear door of the vehicle open;

FIG. 5 is a schematic elevation view of a hinge pin for use in mountingthe flexible membrane deployment system of FIG. 1 on the vehicle of FIG.1;

FIG. 6 is a schematic elevation view of a side panel mounting bar foruse in mounting the flexible membrane deployment system of FIG. 1 on thevehicle of FIG. 1;

FIG. 7 is a schematic elevation view of an alternative side panelmounting bar for use in mounting the flexible membrane deployment systemof FIG. 1 on the vehicle of FIG. 1;

FIG. 8 is a schematic elevation view of a side mounting panel and a rearmounting panel of the flexible membrane deployment system of FIG. 1;

FIG. 9 is a schematic top view of an alternative rear mounting panelthat may be used to replace standard rear cargo doors of the vehicle ofFIG. 1;

FIG. 10 is a detail view of the rear mounting panel of FIG. 9;

FIG. 11 is a schematic perspective view of the rear mounting panel ofFIG. 8 or FIG. 9 including an example integral manifold;

FIG. 12 is a schematic perspective view of a membrane mounting frame foruse with the rear mounting panel of FIG. 8 or FIG. 9;

FIG. 13 is a schematic sectional elevation view of a vehicle includingan alternative flexible membrane deployment system in a deployedprofile;

FIG. 14 is a schematic perspective view of a rear mounting panel thatcan be used with the flexible membrane deployment system of FIG. 13,including an example integral manifold and an example telescopingactuator;

FIG. 15 is a schematic elevation view of another alternative flexiblemembrane deployment system in a first deployed profile;

FIG. 16 is a schematic elevation view of the flexible membranedeployment system of FIG. 16 in a second deployed profile;

FIG. 17 is a schematic perspective view of a rear mounting panel of theflexible membrane deployment system of FIG. 16 including an exampleplurality of integral manifolds;

FIG. 18 is a schematic perspective view of a membrane mounting frame foruse with the rear mounting panel of FIG. 17;

FIG. 19 is a schematic sectional view of the membrane mounting frame ofFIG. 19 along lines 19-19 shown in FIG. 18 and including a plurality ofmembranes mounted thereto;

FIG. 20 is a schematic plan view of an example flexible membrane,including a plurality of sections, that may be used with the flexiblemembrane deployment system of FIG. 1; and

FIG. 21 is a graph depicting an amount of deformation of each of theplurality of sections in FIG. 20 with respect to an amount of appliedforce.

DETAILED DESCRIPTION

The embodiments described herein include an actively inflatable flexiblemembrane coupled to a rear end of a trailer. In some embodiments, theflexible membrane is actively selectively inflatable to differentaerodynamic profiles, and each profile reduces aerodynamic drag inducedby the trailer at a given operating condition of the trailer. In someembodiments. the flexible membrane is mounted to a rear mounting panelthat can serve as the rear cargo door of the trailer, for example byreplacing the traditional rear doors of the trailer in a retrofit.Alternatively, the rear mounting panel can be added over the existingrear cargo doors of the trailer in a swing-away configuration thataccommodates traditional trailer loading and unloading capabilities.Inflation pressure is provided by a dedicated compressor coupled to thetrailer. In certain embodiments, a manifold on the rear mounting panelroutes compressed air between the compressor and the interior spacedefined by the flexible membrane. The flexible membrane may be formedfrom materials having different deformation responses to a given force,in a pattern selected to achieve a desired profile at a given inflationpressure and trailer operating condition. In some embodiments, anadditional vacuum pump is provided to actively deflate the flexiblemembrane to facilitate transitioning of the flexible membrane betweendifferent aerodynamic profiles. A telescoping actuator may be providedto assist in maintaining a stability of a profile of the flexiblemembrane. In some embodiments, a plurality of flexible membranes areactively inflated/deflated in concert to achieve a selected compositeaerodynamic profile.

Unless otherwise indicated, approximating language, such as “generally,”“substantially,” and “about,” as used herein indicates that the term somodified may apply to only an approximate degree, as would be recognizedby one of ordinary skill in the art, rather than to an absolute orperfect degree. Accordingly, a value modified by a term or terms such as“about,” “approximately,” and “substantially” is not to be limited tothe precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value. Here and throughout the specification andclaims, range limitations may be identified. Such ranges may be combinedand/or interchanged, and include all the sub-ranges contained thereinunless context or language indicates otherwise. Additionally, unlessotherwise indicated, the terms “first,” “second,” etc. are used hereinmerely as labels, and are not intended to impose ordinal, positional, orhierarchical requirements on the items to which these terms refer.Moreover, reference to, for example, a “second” item does not require orpreclude the existence of, for example, a “first” or lower-numbered itemor a “third” or higher-numbered item.

FIG. 1 is a schematic perspective view of a vehicle 900 including aflexible membrane deployment system 100 in a deployed profile. FIG. 2 isa schematic elevation view of a plurality of deployed profiles of theflexible membrane deployment system 100. System 100 includes a flexiblemembrane 101 coupled to a rear end 904 of vehicle 900. In the exampleembodiment, vehicle 900 is a tractor-trailer unit including astandard-sized cargo semi-trailer having a front end 902 configured forconnection to the tractor unit (not shown). Alternatively, vehicle 900is any vehicle having a blunt-shaped rear surface profile that tends tocreate aerodynamic drag forces on the vehicle (for example, a bus).

Flexible membrane 101 may be made of any suitable deformable materialthat is substantially impervious to air flow therethrough. Non-limitingexamples of suitable deformable materials include automobile air bagmaterial, coated mine shaft air tunnel materials, parachute material,parasail material, hydraulic accumulator bag material, and anyballoon-type materials. One example is an elastomer-based material.

A perimeter 103 of flexible membrane 101 is sealingly coupled to rearend 904 of vehicle 900, such that a variable-volume cavity 128 isdefined between flexible membrane 101 and rear end 904. Flexiblemembrane deployment system 100 includes a source 601 of pressurized gas129 coupled to trailer 900 and in fluidic communication withvariable-volume cavity 128. In the example embodiment, source 601 is anelectrically driven air compressor. It should be noted that electricalservice, including capacity to drive source 601, is readily available onstandard tractor trailers and other commercial vehicles. Alternatively,source 601 is implemented in any suitable fashion that enables flexiblemembrane deployment system 100 to function as described herein.

Flexible membrane deployment system 100 also includes a controller 600operable to control a flow of the pressurized gas 129 from source 601 tovariable-volume cavity 128. For example, controller 600 includes aregulator 602 responsive to commands entered via a control panel (notshown) located on the vehicle 900, such as in a cab of a tractor unit.More specifically, regulator 602 is selectively operable to increase apressure of pressurized gas 129 in variable-volume cavity 128 such thatflexible membrane 101 moves from a stowed profile 101R, in whichflexible membrane 101 is collapsed against rear end 904 of vehicle 900,to a first deployed profile 101Z, in which flexible membrane 101 ismaintained in a first pre-selected tapered aerodynamic shape projectingrearward from rear end 904. For example, first deployed profile 101Z isselected to reduce an aerodynamic drag induced on vehicle 900 at a givenfirst operating condition (e.g., a first forward travel speed) ofvehicle 900.

In the example embodiment, controller 600 further includes a sourcevalve 603 operable to enable or disable the flow of pressurized gas 129to variable-volume cavity 128 from source 601. For example, source valve603 is responsive to commands entered via a control panel (not shown)located on the vehicle 900, such as in a cab of a tractor unit.

Alternatively, controller 600 includes any suitable elements that enableflexible membrane deployment system 100 to function as described herein.

In the example embodiment, source 601 and controller 600, includingregulator 602 and source valve 603, are housed in an equipmentcompartment 701 attached to vehicle 900, such as on an underside of thesemi-trailer. Alternatively, source 601 and controller 600 are housed inany suitable location that enables flexible membrane deployment system100 to function as described herein.

It should be noted that some examples of vehicle 900 include additionalsources of compressed air, such as for trailer air-brake systems.However, in the example embodiment, source 601 and controller 600 areimplemented independently from such other systems that requirecompressed air. For example, source 601 and controller 600 are not influidic communication with a trailer air-brake system of the trailer900. Thus, in the example embodiment, flexible membrane deploymentsystem 100 may be retrofitted to vehicle 900 without altering anoperation or effectiveness of such other systems.

In the example embodiment, controller 600 further includes a vacuum pump604 in fluidic communication with the variable-volume cavity 128 andoperable to actively extract the pressurized gas 129 from thevariable-volume cavity 128 such that said flexible membrane 101 isreturned from the first deployed profile 101Z to the stowed profile101R. Vacuum pump 604 facilitates an increased speed of deflation ofvariable-volume cavity 128, such as for faster access to unloading ofthe trailer after arrival at a destination. Alternatively,variable-volume cavity 128 is deflated in any suitable fashion thatenables flexible membrane deployment system 100 to function as describedherein. For example, variable-volume cavity 128 is deflated by ventingto atmosphere and manual pressure on an outer surface of flexiblemembrane 101.

In the example embodiment, controller 600 also includes a vacuumregulator 605 responsive to commands entered via a control panel (notshown) located on the vehicle 900, such as in a cab of a tractor unit.More specifically, vacuum regulator 605 is selectively operable todecrease a pressure of pressurized gas 129 in variable-volume cavity 128such that flexible membrane 101 moves back toward stowed profile 101Rfrom first deployed profile 101Z. In the example embodiment, flexiblemembrane deployment system 100 further includes a vacuum valve 606operable to enable or disable a flow of the pressurized gas 129 inducedby vacuum pump 604 from variable-volume cavity 128 into the atmosphere.For example, vacuum valve 606 is responsive to commands entered via acontrol panel (not shown) located on the vehicle 900, such as in a cabof a tractor unit. Vacuum valve 606 may be co-implemented with sourcevalve 603, for example as a bi-directional solenoid valve. In theexample embodiment, vacuum pump 604, vacuum regulator 605, and vacuumvalve 606 are housed in equipment compartment 701 with other elements ofcontroller 600. Alternatively, vacuum pump 604, vacuum regulator 605,and vacuum valve 606 are housed in any suitable location that enablesflexible membrane deployment system 100 to function as described herein.

It should be understood that the overall profile or shape of flexiblemembrane 101 depends on the pressure of pressurized air 129 withinvariable-volume cavity 128 and forces on an exterior surface flexiblemembrane 101 at a given operating condition (due to dynamic pressure attravelling speed, weather, etc.). FIG. 20 is a schematic plan view of anexample embodiment of flexible membrane 101, including a plurality ofsections 800. FIG. 21 is a graph depicting an amount of deformation ofeach of the plurality of sections 800 with respect to an amount ofapplied force. In particular, in FIG. 21, a horizontal axis 801represents deflection and a vertical axis 802 represents applied force.With reference to FIGS. 1, 2, 20, and 21, in some embodiments, flexiblemembrane 101 is formed from plurality of sections 800 having differentdeformation responses to a given air pressure in variable-volume cavity128. For example, flexible membrane 101 includes a peripheral section803, an intermediate section 805, and a central section 807 each havinga different force/deflection curve, as illustrated in FIG. 21. The useof sections 800 having different deflection responses enables theprofile of flexible membrane 101 to be tailored into a specific shapefor a given operating condition. In other words, sections 800 enableflexible membrane 101 to have a multi-faceted profile 810, correspondingto profile 101Z illustrated in FIG. 2, at a given setting of regulator602.

In some embodiments, flexible membrane 101 is a unitary flexiblemembrane 101 having sections 800 formed from a plurality of differentresiliently deformable materials. In other words, the respectivematerials used to form each of sections 800 have different physicalproperties (e.g., different moduli of elasticity) that result in adifferent deformation response to a given loading. For example, flexiblemembrane 101 has a substantially constant thickness across sections 800,and the different materials used to form sections 803, 805, and 807 eachdeform differently, in response to a given pressure of the pressurizedgas 129 in the variable-volume cavity 128, to define the preselectedtapered aerodynamic shape of profile 810. In other embodiments, flexiblemembrane 101 is a unitary flexible membrane 101 formed from a singleresiliently deformable material across sections 800, but havingdifferent membrane thicknesses in each of sections 800. For example, thedifferent membrane thickness of the single material used to formsections 803, 805, and 807 cause each section to deform differently, inresponse to a given pressure of the pressurized gas 129 in thevariable-volume cavity 128, to define the preselected taperedaerodynamic shape of profile 810. In further embodiments, flexiblemembrane 101 includes sections 800 defined by a combination of differentmaterials and different membrane thicknesses that cause each section todeform differently, in response to a given pressure of the pressurizedgas 129 in the variable-volume cavity 128, to define the preselectedtapered aerodynamic shape of profile 810.

Alternatively, flexible membrane 101 does not include sections 800having different deformation responses.

In the example embodiment, flexible membrane 101 also includespre-formed crease or fold lines 811 extending therein. In this context,the term “pre-formed” means, e.g., formed prior to installation offlexible membrane deployment system 100 on vehicle 900. For example,fold lines 811 extend across the plurality of sections 800 and cooperatewith sections 800 to further define multi-faceted profile 810. Foldlines 811 may be pre-formed in flexible membrane 101 in any suitablefashion that enables flexible membrane deployment system 100 to functionas described herein. Alternatively, flexible membrane 101 does notinclude fold lines 811.

Although flexible membrane 101 in an unforced state is illustrated assubstantially flat in FIG. 20, with perimeter 103 defined by asubstantially rectangular boundary, it should be understood thatflexible membrane 101 and/or perimeter 103 may have any suitable shapein the unforced state that enables flexible membrane deployment system100 to function as described herein. When flexible membrane 101 iscoupled to rear end 904 of vehicle 900, perimeter 103 defines an openingin flexible membrane 101 through which variable-volume cavity 128 may beinflated or deflated.

Returning to FIGS. 1 and 2, in the example embodiment, controller 600 isfurther operable to control the flow of pressurized gas 129 from source601 to variable-volume cavity 128 such that flexible membrane 101 ismovable between the first deployed profile 101Z and a second deployedprofile 101A, wherein flexible membrane 101 is maintained in a secondpre-selected tapered aerodynamic shape projecting rearward from the rearend 904. More specifically, the second pre-selected tapered aerodynamicshape is different from the first pre-selected tapered aerodynamicshape. For example, second deployed profile 101A is selected to reducean aerodynamic drag induced on vehicle 900 at a given second operatingcondition (e.g., a second forward travel speed) of vehicle 900. In someexamples, the different forward travel speeds may correspond to 55 milesper hour and 75 miles per hour.

Moreover, in some embodiments, controller 600 is further operable tocontrol the flow of pressurized gas 129 from source 601 tovariable-volume cavity 128 such that flexible membrane 101 is movable toother deployed profiles in addition to the first deployed profile 101Zand the second deployed profile 101A. For example, regulator 602 isoperable to fine-tune the flow of pressurized gas 129 at a given forwardtravel speed to further reduce aerodynamic drag or otherwise improvedrivability of vehicle 900 based on environmental conditions (e.g.,weather). In certain embodiments, controller 600 is responsive tocommands entered via a control panel (not shown) located on the vehicle900, such as in a cab of a tractor unit, to adjust first deployedprofile 101Z to third deployed profile 101Y, and/or to adjust seconddeployed profile 101A to fourth deployed profile 101X, in response toambient wind or atmospheric pressure conditions on vehicle 900.

In the example embodiment, flexible membrane deployment system 100further includes a rear mounting panel 204 coupled to rear end 904 ofvehicle 900. More specifically, perimeter 103 of flexible membrane 101is coupled to rear end 904 of vehicle 900 via coupling to rear mountingpanel 204. Alternatively, perimeter 103 of flexible membrane 101 iscoupled to rear end 904 in any suitable fashion that enables flexiblemembrane deployment system 100 to function as described herein.

In the example embodiment, rear mounting panel 204 is fabricated from alightweight, yet rigid and impact-resistant material. For example, rearmounting panel 204 is fabricated from plastic or machined aluminum.Alternatively, rear mounting panel 204 is fabricated from any suitablematerial that enables flexible membrane deployment system 100 tofunction as described herein

In some embodiments, rear mounting panel 204 is added over existing rearcargo doors 901 of vehicle 900 in a swing-away configuration thataccommodates conventional trailer loading and unloading capabilities.FIG. 3 is a schematic bottom view of a rear portion of vehicle 900including flexible membrane deployment system 100 in a collapsedprofile. FIG. 4A is a schematic perspective view of vehicle 900including flexible membrane deployment system 100 in a vehicle-unloadingconfiguration. FIG. 4B is a schematic perspective view of the rearportion of vehicle 900 including flexible membrane deployment system 100in the vehicle-unloading configuration and one of rear cargo doors 901of the vehicle open to enable access to an interior of vehicle 900(e.g., a cargo area of a semi-trailer) via a rear cargo opening 903.FIG. 8 is a schematic elevation view of a side mounting panel 203 andrear mounting panel 204.

With reference to FIGS. 1, 3, 4A, 4B, and 8, in some embodiments,flexible membrane deployment system 100 includes swing panel 203mountable on an exterior of a side wall 906 of vehicle 900. Swing panel203 enables rear mounting panel 204 to be moved between a first positionparallel and adjacent to rear end 904 (shown in FIG. 3), and a secondposition parallel and adjacent to the exterior of side wall 906 (shownin FIG. 4A).

In the example embodiment, swing panel 203 includes a pair of hingejoints 211 on opposing side edges thereof. A first of the pair of hingejoints 211 is rotatably mounted to side wall 906 of vehicle 900. Forexample, FIG. 6 is a schematic elevation view of a side panel mountingbar 201 for use in mounting the first hinge joint 211 of swing panel 203adjacent to side wall 906 of vehicle 900. Side panel mounting bar 201 isconfigured to be fixedly mounted along the exterior of side wall 906 andincludes a plurality of mounts 217, in the form of pegs, arrangedvertically therealong. More specifically, mounts 217 are spaced andoriented to register with elements of first hinge joint 211 of swingpanel 203, such that when swing panel 203 is lowered downward, theelements of the first hinge joint 211 receive respective pegs torotatably couple swing panel 203 to side panel mounting bar 201. Foranother example, FIG. 7 is a schematic elevation view of an alternativeside panel mounting bar 201 for use in mounting the first hinge joint211 of swing panel 203 adjacent to side wall 906 of vehicle 900. Thealternative side panel mounting bar 201 includes plurality of mounts 217in the form of pillow blocks, arranged vertically therealong, spaced andoriented to register with elements of first hinge joint 211 of swingpanel 203, such that the elements of the first hinge joint 211 arecoupleable to respective pillow blocks to rotatably couple swing panel203 to side panel mounting bar 201. Alternatively, the first hinge joint211 of swing panel 203 is rotatably mountable to the exterior of sidewall 906 in any suitable fashion that enables flexible membranedeployment system 100 to function as described herein.

In the example embodiment, the opposite second pair of hinge joints 211of swing panel 203 is rotatably mounted to rear mounting panel 204. Forexample, rear mounting panel 204 includes a hinge joint 213 configuredto cooperate with the second hinge joint 211 of swing panel 203, and ahinge pin 202, shown in FIG. 5, is inserted through the cooperatinghinge joints 211 and 213 to rotatably couple rear mounting panel 204 toswing panel 203. Alternatively, rear mounting panel 204 is rotatablycoupled to swing panel 203 in any suitable fashion that enables flexiblemembrane deployment system 100 to function as described herein.

In the example embodiment, rear mounting panel 204 further includes afastener 210 on a side edge opposite hinge joint 213. Fastener 210 isoperable to selectively engage rear end 904 to secure rear mountingpanel 204 in the first position during transit of vehicle 900. Forexample, fastener 210 is a hinged door fastener configured to mate withan eye bolt mounted on rear end 904 to provide a locking mechanism forrear mounting panel 204 in the first position. In some embodiments,fastener 210 is further operable to selectively engage side wall 906 tosecure rear mounting panel 204 in the second position duringloading/unloading of vehicle 900. Alternatively, rear mounting panel 204is securable in the first position and/or the second position in anysuitable fashion that enables flexible membrane deployment system 100 tofunction as described herein.

In the example embodiment, swing panel 203 is sized such that, in thesecond position, swing panel 203 and rear mounting panel 204 are offsetfrom rear end 904 by a sufficient distance to enable rear cargo door 901of vehicle 900 to be rotated open and flush directly against theexterior of side wall 906, as shown in FIG. 4B, to enable conventionaltrailer unloading operations. For example, a width x of swing panel 203(shown in FIG. 8) is approximately two inches wider than a width y(shown in FIG. 4B) of rear cargo door 901, enabling flexible membranedeployment system 100 to be completely cleared from a working area ofrear cargo doors 901/rear cargo opening 903 during loading/unloading ofvehicle 900. In some embodiments, rear cargo doors 901 arestandard-sized semi-trailer rear cargo doors.

In some embodiments, rather than installing flexible membrane deploymentsystem 100 over rear cargo doors 901, rear mounting panel 204 may beused to replace rear cargo doors 901 as a one-piece rear cargo door usedto directly seal rear cargo opening 903 during transit of vehicle 900.FIG. 9 is a schematic top view of an alternative rear mounting panel 204that may be used to seal rear cargo opening 903 when rear mounting panel204 is in the first position. FIG. 10 is a detail view of rear mountingpanel 204 shown in FIG. 9. The alternative rear mounting panel 204 issubstantially similar to rear mounting panel 204 as described above,including fastener 210 operable to selectively engage rear end 904 tosecure rear mounting panel 204 in the first position during transit ofvehicle 900. However, rather than hinge joint 213 configured torotatably mount to swing panel 203, rear mounting panel 204 includeshinge joint 218 configured to rotatably mount directly to rear end 904in place of the left-hand (or alternatively, the right-hand) standardrear cargo door 901. Alternatively, rear mounting panel 204 isconfigured for installation on rear end 904 in any suitable fashion thatenables flexible membrane deployment system 100 to function as describedherein.

In the example embodiment, rear mounting panel 204 configured to replacerear cargo doors 901 includes an interior-facing panel 216 and anexterior-facing panel 219 coupled together in face-to-face-relationship.More specifically, interior-facing panel 216 is configured to bereceived within rear cargo opening 903 when rear mounting panel 204 isclosed, and exterior-facing panel 219 is configured to extend rearwardfrom rear cargo opening 903 when rear mounting panel 204 is closed.Flexible membrane 101 is coupled to exterior-facing panel 219.Exterior-facing panel 219 extending rearward from rear cargo opening 903facilitates reducing a risk of interference between flexible membrane101 and rear end 904 when flexible membrane 101 is deployed andretracted. Alternatively, rear mounting panel 204 is configured tocouple over and seal rear cargo opening 903 in any suitable fashion thatenables flexible membrane deployment system 100 to function as describedherein.

In the example embodiment, interior-facing panel 216 includes a bevel212 shaped complementary to an indent of rear end 904 along a perimeterof rear cargo opening 903. More specifically, bevel 212 enablesinterior-facing panel 216 to achieve a better seal against rear end 904when rear mounting panel 204 is closed over rear cargo opening 903. Insome embodiments, a compressible material 215 is coupled tointerior-facing panel 216 along bevel 212. Compressible material 215facilitates adjusting a fit between interior-facing panel 216 and rearcargo opening 903. Alternatively, interior-facing panel 216 does notinclude bevel 212 and/or compressible material 215.

FIG. 11 is a schematic perspective view of rear mounting panel 204 ofFIG. 8 or FIG. 9 including an example integral manifold 207. Withreference to FIGS. 1, 2, and 11, in the example embodiment, anexterior-facing surface 221 of rear mounting panel 204 includes a panelperimeter region 252 and a panel interior region 254 surrounded by panelperimeter region 252. Panel perimeter region 252 is configured forcoupling to perimeter 103 of flexible membrane 101, and panel interiorregion 254 is configured to cooperate with flexible membrane 101 todefine variable-volume cavity 128.

In the example embodiment, manifold 207 is integral to rear mountingpanel 204 in the sense that rear mounting panel 204 includes one or moreair channels 222 defined internally within rear mounting panel 204. Airchannels 222 are in fluidic communication with an inlet port 209 definedon rear mounting panel 204. In turn, inlet port 209 is configured forcoupling in fluidic communication with source 601. For example, inletport 209 is defined in a bottom edge 224 of rear mounting panel 204, andcompartment 701 includes an air line (not shown) in series with sourcevalve 603 that extends to rear end 904 for coupling (e.g., via aquick-disconnect connector) to inlet port 209 when rear mounting panel204 is in the first position. Alternatively, inlet port 209 is definedat any suitable location on rear mounting panel 204, and/or inlet port209 is configured for coupling in fluidic communication with source 601in any suitable fashion, that enables flexible membrane deploymentsystem 100 to function as described herein.

In the example embodiment, the one or more air channels 222 are furtherin fluidic communication with at least one cavity port 206. In turn,cavity ports 206 extend through exterior-facing surface 221, withinpanel interior region 254, into fluidic communication withvariable-volume cavity 128. Thus, manifold 207 defines a flow path forcompressed air 129 from source 601, through inlet port 209, the one ormore air channels 222, and the at least one cavity port 206, intovariable-volume cavity 128. Alternatively, manifold 207 defines a flowpath for compressed air 129 from source 601, through rear mounting panel204, and into variable-volume cavity 128 in any suitable fashion thatenables flexible membrane deployment system 100 to function as describedherein.

In some embodiments, the use of manifold 207 integral to rear mountingpanel 204 simplifies an installation of flexible membrane deploymentsystem 100 on vehicle 900. More specifically, the installation of rearmounting panel 204, whether using swing panel 203 or in replacement ofrear cargo doors 901, simultaneously provides both a support structurefor flexible membrane 101 and a pre-defined air flow path between source601 of compressed air 129 and variable-volume cavity 128. Alternatively,manifold 207 is other than integral to rear mounting panel 204. Forexample, manifold 207 is provided as a flexible conduit between source601 and variable-volume cavity 128 that is structurally separate fromrear mounting panel 204.

In the example embodiment, air channels 222 are further in fluidiccommunication with an outlet port 208 defined on rear mounting panel204. In turn, outlet port 208 is configured for coupling in selectivefluidic communication with vacuum pump 604. For example, outlet port 208is defined in bottom edge 224 of rear mounting panel 204, andcompartment 701 includes an air line (not shown) in series with vacuumvalve 606 that extends to rear end 904 for coupling (e.g., via aquick-disconnect connector) to outlet port 208 when rear mounting panel204 is in the first position. Alternatively, outlet port 208 is definedat any suitable location on rear mounting panel 204, and/or outlet port208 is configured for coupling in fluidic communication with vacuum pump604 in any suitable fashion, that enables flexible membrane deploymentsystem 100 to function as described herein. In some embodiments, the useof a same manifold 207 for fluidic communication of variable-volumecavity 128 with both source 601 and vacuum pump 604 reduces a sizeand/or simplifies an installation of flexible membrane deployment system100. Alternatively, vacuum pump 604 is coupled in selective fluidiccommunication with variable-volume cavity 128 in any suitable fashionthat enables flexible membrane deployment system 100 to function asdescribed herein, or flexible membrane deployment system 100 does notinclude vacuum pump 604. For example, outlet port 208 is vented toatmosphere.

FIG. 12 is a schematic perspective view of a membrane mounting frame 301for use with rear mounting panel 204 shown in FIG. 8 or FIG. 9. In theexample embodiment, flexible membrane deployment system 100 furtherincludes membrane mounting frame 301 configured to secure flexiblemembrane 101 to rear mounting panel 204.

With reference to FIGS. 1, 11, and 12, in the example embodiment,membrane mounting frame 301 includes a plurality of openings 302arranged to register with a corresponding plurality of mounting openings205 defined in panel perimeter region 252 of rear mounting panel 204.After perimeter 103 of flexible membrane 101 is sandwiched betweenmembrane mounting frame 301 and panel perimeter region 252, suitablefasteners (not shown) are inserted into registered pairs of openings302, 205 and tightened to secure perimeter 103 to rear mounting panel204. Perimeter 103 may include pre-defined openings configured toregister with openings 302, 205, or the fastener installation processitself may form suitable registered openings in perimeter 103. In theillustrated embodiment, eight pairs of openings 302, 205 are provided.Alternatively, any suitable number of openings is provided that enablesflexible membrane deployment system 100 to function as described herein.

In the example embodiment, a portion of the flexible material used toform flexible membrane 101 is compressed directly between membranemounting frame 301 and panel perimeter region 252, and this portionfunctions as a compressible sealing material that facilitates anair-tight seal of variable-volume cavity 128 around perimeter 103.Additionally or alternatively, a groove (not shown) is formed in panelperimeter region 252 and/or membrane mounting frame 301, and an O-ring(not shown) is positioned in the groove to facilitate an air-tight sealof variable-volume cavity 128 around perimeter 103.

Alternatively, flexible membrane 101 is coupled to rear mounting panel204 in any suitable fashion that enables flexible membrane deploymentsystem 100 to function as described herein.

FIG. 13 is a schematic sectional elevation view of vehicle 900 includingan alternative flexible membrane deployment system 100 in a deployedprofile 101C. FIG. 14 is a schematic perspective view of a rear mountingpanel 204 that can be used with the alternative flexible membranedeployment system of FIG. 13 The illustrated flexible membranedeployment system 100 includes elements substantially identical to thosedescribed above, but further includes a telescoping actuator 401 coupledto rear end 904 of vehicle 900.

Telescoping actuator 401 includes a distal end 412 selectively movable,within variable-volume cavity 128, between a retracted position (shownin FIG. 14), in which distal end 412 is proximate to rear end 904, and afirst extended position (shown in FIG. 13), in which distal end 412(identified with a dashed leader line) is spaced apart from rear end 904at a first distance. Controller 600 (shown in FIG. 1) and telescopingactuator 401 are cooperatively operable to move flexible membrane 101from stowed profile 101R (shown in FIG. 2) to a first deployed profile101B (showed in dashed lines). More specifically, the first extendedposition causes distal end 412 to extend at or near a distal tip offlexible membrane 101 in deployed profile 101B. First deployed profile101B corresponds to a first pre-selected tapered aerodynamic shapeprojecting rearward from rear end 904. In some embodiments, telescopingactuator 401 in the first extended position adds rigidity to flexiblemembrane 101 in deployed profile 101B, for example stabilizing flexiblemembrane 101 against cross-winds and thereby improving drag-reducingcharacteristics of deployed profile 101B.

Telescoping actuator 401 in the retracted position is configured toavoid interference with flexible membrane 101 in stowed profile 101R. Inother words, telescoping actuator 401 is collapsible into the retractedposition to enable flexible membrane 101 to be collapsed against rearend 904 when flexible membrane deployment system 100 is not in use, forexample during loading and unloading of vehicle 900. In the exampleembodiment, telescoping actuator 401 in the retracted position iscollapsed into a disk-like configuration. Alternatively, telescopingactuator 401 in the retracted position has any suitable shape thatenables flexible membrane deployment system 100 to function as describedherein.

In the example embodiment, telescoping actuator 401 is furtherselectively movable, within variable-volume cavity 128, between thefirst extended position and a second extended position, in which distalend 412 (identified with a solid leader line) is spaced apart from rearend 904 at a second distance greater than the first distance. Morespecifically, controller 600 and telescoping actuator 401 arecooperatively operable to further move flexible membrane 101 betweenfirst deployed profile 101B and a second deployed profile 101C. Seconddeployed profile 101C corresponds to a second pre-selected taperedaerodynamic shape projecting rearward from rear end 904 and differentfrom the first pre-selected tapered aerodynamic shape corresponding tofirst deployed profile 101B. In some embodiments, telescoping actuator401 in the second extended position adds rigidity to flexible membrane101 in deployed profile 101C, for example stabilizing flexible membrane101 against cross-winds and thereby improving drag-reducingcharacteristics of deployed profile 101C.

In some embodiments, controller 600 is operable to maintain pressurizedgas 129 in variable-volume cavity 128 at a substantially constantpressure while flexible membrane 401 is maintained in either of firstdeployed profile 101B and second deployed profile 101C. In other words,telescoping actuator 401 is capable of moving flexible membrane 101between different deployed profiles, e.g., corresponding to differentoperating conditions of vehicle 900, without adjustment of the pressurewithin variable-volume cavity 128. Additionally or alternatively, incertain embodiments, controller 600 is operable to maintain pressurizedgas 129 in the variable-volume cavity at a first pressure while flexiblemembrane 101 is maintained in first deployed profile 101B, and at asecond pressure while flexible membrane 101 is maintained in seconddeployed profile 101C, the second pressure being different from thefirst pressure. In other words, telescoping actuator 401 is capable ofmoving flexible membrane 101 between different deployed profiles, e.g.,corresponding to different operating conditions of vehicle 900, incooperation with an adjustment of the pressure by regulator 602 withinvariable-volume cavity 128.

In the example embodiment, telescoping actuator 401 is mounted on rearmounting panel 204. For example, as described above, rear mounting panel204 includes manifold 207 integral to rear mounting panel 204 and influidic communication with source 601 via inlet port 209, and withvacuum pump 604 via outlet port 208. Alternatively, telescoping actuator401 is mounted to rear end 904 in any suitable fashion that enablesflexible membrane deployment system 100 to function as described herein.

In the example embodiment, rear mounting panel 204 further includes anactuation system for telescoping actuator 401. For example, telescopingactuator 401 is pneumatically actuated. Accordingly, rear mounting panel204 includes air lines 407 and 406 in fluidic communication betweentelescoping actuator 401 and, respectively, an actuator inlet port 403and an actuator outlet port 402 defined on a bottom edge of rearmounting panel 204. In turn, actuator inlet port 403 and actuator outletport 402 are in respective fluidic communication (e.g., viaquick-disconnect connectors) with an actuator pneumatic source (notshown) and an actuator vacuum pump (not shown). For example, theactuator source and actuator vacuum pump, similar to source 601 andvacuum pump 604, are positioned in compartment 701 (shown in FIG. 1) andresponsive to commands entered via a control panel (not shown) locatedon the vehicle 900, such as in a cab of a tractor unit. Pressurized airsupplied through actuator inlet port 403 causes telescoping actuator 401to extend, and vacuum pressure induced via actuator outlet port 402causes telescoping actuator 401 to retract.

Alternatively, telescoping actuator 401 is actuatable in any suitablefashion that enables flexible membrane deployment system 100 to functionas described herein.

FIG. 15 is a schematic elevation view of another alternative flexiblemembrane deployment system 100 in a first deployed profile 101D. FIG. 16is a schematic elevation view of flexible membrane deployment system 100of FIG. 16 in a second deployed profile 101E. FIG. 17 is a schematicperspective view of an example rear mounting panel 204A of the flexiblemembrane deployment system of FIG. 15, and FIG. 18 is a schematicperspective view of a membrane mounting plate 306 for use with rearmounting panel 204A.

With reference to FIGS. 15-18, in the illustrated embodiment, flexiblemembrane deployment system 100 includes a plurality of flexiblemembranes 101. Each flexible membrane 101 of the plurality of flexiblemembranes 101 includes a perimeter 303 coupled to rear end 904 ofvehicle 900, such that a respective variable-volume cavity 128 isdefined between each flexible membrane 101 and rear end 904. At leastone source 601 of pressurized gas 129 is coupled to vehicle 900, such aswithin equipment compartment 701, and in fluidic communication with therespective variable-volume cavity 128 defined by each flexible membrane101. Moreover, flexible membrane deployment system 100 includescontroller 600, such as within equipment compartment 701, operable tocontrol a flow of the pressurized gas from the at least one source 601to the respective variable-volume cavity 128 defined by each flexiblemembrane 101. For example, controller 600 includes a plurality of sourcevalves 603 each separately responsive to commands entered via a controlpanel (not shown) located on the vehicle 900, such as in a cab of atractor unit. In the illustrated embodiment, one source 601 suppliesmultiple valves 603. Alternatively, each of a plurality of sources 601supplies a different group of valves 603. Similarly, in someembodiments, a single regulator (not shown), similar to regulator 602shown in FIG. 1, controls a pressure level available at the plurality ofsource valve 603. Alternatively, each of a plurality of sources 601controls the pressure level for a different group of valves 603.

More specifically, controller 600 is operable such that the plurality offlexible membranes 101 is movable between a first deployed profile 101D(shown in FIG. 15), in which the plurality of flexible membranes 101cooperate to maintain a first pre-selected tapered aerodynamic shapeprojecting rearward from rear end 904 of vehicle 900, and a seconddeployed profile 101E (shown in FIG. 16), in which the plurality offlexible membranes 101 cooperate to maintain a second pre-selectedtapered aerodynamic shape projecting rearward from rear end 904. Inparticular, the second pre-selected tapered aerodynamic shape isdifferent from the first pre-selected tapered aerodynamic shape. Inother words, each flexible membrane 101 is independently inflatable, andthe pattern of inflation and deflation of the plurality of flexiblemembranes 101 establishes the cooperative deployed profile 101D or 101E.For example, first deployed profile 101D is selected to reduce anaerodynamic drag induced on vehicle 900 at a given first operatingcondition (e.g., a first forward travel speed) of vehicle 900, andsecond deployed profile 101E is selected to reduce an aerodynamic draginduced on vehicle 900 at a given second operating condition (e.g., asecond forward travel speed) of vehicle 900.

It should be understood that the number and arrangement of flexiblemembranes 101 and the patterns of inflation and deflation illustrated inFIGS. 15 and 16 are examples only, and in no way intended to belimiting. Many other suitable numbers and arrangements of flexiblemembranes 101 and/or suitable patterns of inflation and deflation that,for example, establish different cooperative deployed profiles arecontemplated by the disclosure.

In some embodiments, flexible membrane deployment system 100 furtherincludes at least one vacuum pump 604 (shown in FIG. 1) in fluidiccommunication with the respective variable-volume cavity 128 defined byeach flexible membrane 101, and operable to extract the pressurized gas129 from the variable-volume cavity 128 such that each flexible membrane101 is returned from first deployed profile 101D to stowed profile 101R.As discussed above, the at least one vacuum pump 604 facilitates anincreased speed of deflation of each variable-volume cavity 128, such asfor faster access to unloading of the trailer after arrival at adestination. Alternatively, each variable-volume cavity 128 is deflatedin any suitable fashion that enables flexible membrane deployment system100 to function as described herein. For example, each variable-volumecavity 128 is deflated by venting to atmosphere and manual pressure onan outer surface of the respective flexible membrane 101.

In the example embodiment, flexible membrane deployment system 100includes an alternative embodiment of rear mounting panel 204,designated rear mounting panel 204A, coupled to rear end 904 of vehicle900, and the respective perimeter 303 of each flexible membrane 101 iscoupled to rear mounting panel 204A. For example, in some embodiments,flexible membrane deployment system 100 includes swing panel 203mountable on the exterior of side wall 906 of vehicle 900, as describedabove, enabling rear mounting panel 204A to be moved between the firstposition parallel and adjacent to rear end 904 (shown in FIG. 3), andthe second position parallel and adjacent to the exterior of side wall906 (shown in FIG. 4A).

In the example embodiment, rear mounting panel 204A includes a pluralityof manifolds 207 defined internally therein. Each of the plurality ofmanifolds 207 is in fluidic communication with a corresponding one ofthe plurality of regulators 602, and with a corresponding at least onecavity port, such as cavity ports 206 or 506. In turn, the at least onecavity port is in fluidic communication with the respectivevariable-volume cavity 128 defined by each of a corresponding subset ofthe plurality of flexible membranes 101.

In the example embodiment, each manifold 207 is integral to rearmounting panel 204A in the sense that rear mounting panel 204A includesone or more sets of air channels 222, 522 defined internally within rearmounting panel 204A. More specifically, a first of the plurality ofmanifolds 207 includes a first set of one or more air channels 222 influidic communication with an inlet port 209 defined on rear mountingpanel 204A. In turn, inlet port 209 is configured for coupling influidic communication with the at least one source 601 and a first ofthe plurality of source valves 603. For example, inlet port 209 is againdefined in bottom edge 224 of rear mounting panel 204A, and compartment701 includes an air line (not shown) in series with the first sourcevalve 603 that extends to rear end 904 for coupling (e.g., via aquick-disconnect connector) to inlet port 209 when rear mounting panel204A is in the first position. Similarly, a second of the plurality ofmanifolds 207 includes a second set of one or more air channels 522 influidic communication with a second inlet port 509 defined on rearmounting panel 204A. In turn, second inlet port 209 is configured forcoupling in fluidic communication with the at least one source 601 and asecond of the plurality of source valves 603. For example, inlet port509 is also defined in bottom edge 224 of rear mounting panel 204A, andcompartment 701 includes a second air line (not shown) in series withthe second source valve 603 that extends to rear end 904 for coupling(e.g., via a quick-disconnect connector) to inlet port 509 when rearmounting panel 204A is in the first position.

Alternatively, inlet ports 209 and/or 509 are defined at any suitablelocation on rear mounting panel 204A, and/or inlet ports 209 and/or 509are configured for coupling in fluidic communication with the at leastone source 601 and the respective first and second source valves 603 inany suitable fashion, that enables flexible membrane deployment system100 to function as described herein.

In the example embodiment, the one or more air channels 222 are furtherin fluidic communication with at least one cavity port 206, and the oneor more air channels 522 are further in fluidic communication with atleast one cavity port 506. In turn, each of cavity ports 206 and 506extend through exterior-facing surface 221 into fluidic communicationwith a corresponding variable-volume cavity 128 defined by the pluralityof flexible membranes 101. Thus, a first manifold 207 defines a flowpath for compressed air 129 from the at least one source 601, throughinlet port 209, the one or more air channels 222, and the at least onecavity port 206, into the variable-volume cavities 128 associated with afirst set 111 of the plurality of flexible membranes 101, and a secondmanifold 207 defines a flow path for compressed air 129 from the atleast one source 601, through inlet port 509, the one or more airchannels 522, and the at least one cavity port 506, into thevariable-volume cavities 128 associated with a second set 113 of theplurality of flexible membranes 101. Alternatively, the plurality ofmanifolds 207 defines respective flow paths for compressed air 129through respective source valves 603 from the at least one source 601,through rear mounting panel 204A, and into the respectivevariable-volume cavities 128 of sets 111 and 113 of flexible membranes101 in any suitable fashion that enables flexible membrane deploymentsystem 100 to function as described herein.

In some embodiments, the use of plurality of manifolds 207 integral torear mounting panel 204A simplifies an installation of flexible membranedeployment system 100 on vehicle 900. More specifically, theinstallation of rear mounting panel 204A, whether using swing panel 203or in replacement of rear cargo doors 901, simultaneously provides botha support structure for the plurality of flexible membranes 101 andpre-defined independent air flow paths between the at least one source601 of compressed air 129 and the variable-volume cavities 128associated with respective sets 111 and 113 of the plurality of flexiblemembranes 101. Accordingly, sets 111 and 113 of flexible membranes 101are independently inflatable and deflatable to move between cooperativedeployed profiles 101D and 101E. Alternatively, the plurality ofmanifolds 207 is other than integral to rear mounting panel 204A. Forexample, at least one manifold 207 is provided as a flexible conduitbetween the at least one source 601 and a set of variable-volumecavities 128 that is structurally separate from rear mounting panel 204.

In the example embodiment, air channels 222 of the first manifold 207are further in fluidic communication with an outlet port 208 defined onrear mounting panel 204A, and air channels 522 of the second manifold207 are further in fluidic communication with an outlet port 508 definedon rear mounting panel 204A. In turn, outlet ports 208 and 508 are eachconfigured for coupling in selective fluidic communication with at leastone vacuum pump (not shown) configured to extract pressurized gas 129from the respective sets 111 and 113 of variable-volume cavities suchthat each flexible membrane 101 is moved from cooperating in at leastone of the first and second deployed profiles 101D, 101E to cooperatingin stowed profile 101R, in which each flexible membrane 101 is collapsedagainst rear end 904 of vehicle 900. For example, the at least onevacuum pump is positioned in equipment compartment 701 and functionswith the plurality of manifolds 207 similar to as described above forvacuum pump 604 (shown in FIG. 1).

It should be understood that the number and arrangement of plurality ofmanifolds 207 and the patterns of cavity outlet ports 206, 506illustrated in FIG. 17 are examples only, and in no way intended to belimiting. Many other suitable numbers and arrangements of manifolds 207and/or suitable patterns of cavity outlet ports 206, 506 that, forexample, support different numbers and arrangements of flexiblemembranes 101 are contemplated by the disclosure.

Membrane mounting plate 306 is configured to secure plurality offlexible membranes 101 to rear mounting panel 204A. In the exampleembodiment, an interior region of membrane mounting plate 306 includes aplurality of apertures 307 defined in membrane mounting plate 306 andextending therethrough. Each aperture 307 aligns with a correspondingone of cavity ports 206, 506 to receive a neck 310 of a correspondingflexible membrane 101 therethrough. Further in the example embodiment,each aperture 307 is bounded by a hollow post 308. Each hollow post 308is configured to receive neck 310 of the corresponding flexible membrane101 therethrough, and to further receive a folded-over portion of neck310 of the corresponding flexible membrane 101, defining perimeter 303,against an exterior surface of post 308. Moreover, the exterior surfaceof each post 308 overlaid by perimeter 303 is configured to be receivedin an interference fit against an interior surface of the aligned one ofcavity ports 206, 506 when membrane mounting plate 306 is secured torear mounting panel 204A, thereby securing perimeter 303 of eachflexible membrane 101 to rear mounting panel 204A. For example, eachpost 308 is configured to extend into the corresponding one of cavityports 206, 506 by a distance 304. Alternatively, perimeter 303 of eachflexible membrane 101 is secured to rear mounting panel 204A in anysuitable fashion that enables flexible membrane deployment system 100 tofunction as described herein.

In the example embodiment, flexible membrane deployment system 100further includes resilient O-rings 309 each configured to bias perimeter303 of a respective flexible membrane 101 against a base of thecorresponding post 308, and/or to further seal perimeter 303 aftercoupling of membrane mounting plate 306 to rear mounting panel 204A.Alternatively, flexible membrane deployment system 100 does not includeO-rings 309.

In the example embodiment, similar to membrane mounting frame 301discussed above, membrane mounting plate 306 includes a plurality ofopenings 302 arranged to register with a corresponding plurality ofmounting openings 205 defined in rear mounting panel 204A. Afterperimeter 303 of each flexible membrane 101 is coupled to a respectivepost 308 as described above, suitable fasteners (not shown) are insertedinto registered pairs of openings 302, 205 and tightened to furthersecure perimeter 303 of each flexible membrane 101 to rear mountingpanel 204A. Alternatively, membrane mounting plate 306 is furthersecured to rear mounting panel 204A in any suitable fashion that enablesflexible membrane deployment system 100 to function as described herein.

The above-described embodiments of a flexible membrane deployment systemovercome at least some disadvantages of known systems for reducingaerodynamic drag on a vehicle, such as a semi-trailer. Specifically, thesystem is actuated in a fashion that is independent of vehicle speed toactively change the rear profile of the vehicle among a number ofdifferent shapes. Also specifically, in some embodiments, the systemincludes a rear mounting panel that simultaneously provides both asupport structure for a flexible membrane and a pre-defined air flowpath between a source of compressed air and a variable-volume cavitydefined by the membrane.

Exemplary embodiments of a flexible membrane deployment system aredescribed above in detail. The methods and apparatus are not limited tothe specific embodiments described herein, but rather, components ofsystems and/or steps of the method may be utilized independently andseparately from other components and/or steps described herein. Forexample, the methods and apparatus may also be used in combination withother vehicles, and are not limited to practice with only a semi-traileras described herein.

Although specific features of various embodiments of the disclosure maybe shown in some drawings and not in others, this is for convenienceonly. Moreover, references to “the example embodiment” or “someembodiments” in the above description are not intended to be interpretedas excluding the existence of additional embodiments that alsoincorporate the recited features. In accordance with the principles ofthe disclosure, any feature of a drawing may be referenced and/orclaimed in combination with any feature of any other drawing.

This written description uses examples to illustrate the disclosure,including the best mode, and also to enable any person skilled in theart to practice the disclosure, including making and using any devicesor systems and performing any incorporated methods. The patentable scopeof the disclosure is defined by the claims, and may include otherexamples that occur to those skilled in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal language of the claims.

What is claimed is:
 1. A vehicle comprising: a pressurization source; arear panel comprising a plurality of air channels, each of saidplurality of air channels extending parallel to a plane defined by saidrear panel, said plurality of air channels in fluidic communication withsaid pressurization source; a flexible membrane comprising a perimeter,said perimeter sealingly coupled to said rear panel; and at least oneport defined in and extending through said rear panel, said at least oneport enclosed by said perimeter and in fluidic communication with saidplurality of air channels.
 2. The vehicle according to claim 1, whereinsaid pressurization source comprises an electrically driven aircompressor.
 3. The vehicle according to claim 1, further comprising anair-brake system, wherein said pressurization source is not in fluidiccommunication with said air-brake system.
 4. The vehicle according toclaim 1, wherein said flexible membrane comprises a unitary flexiblemembrane formed from a plurality of different resiliently deformablematerials, wherein said plurality of different resiliently deformablematerials each deform differently in response to a given pressure. 5.The vehicle according to claim 1, wherein said flexible membranecomprises a unitary flexible membrane formed from a resilientlydeformable material and having portions that each deform differently inresponse to a given pressure.
 6. The vehicle according to claim 1,further comprising a membrane mounting frame, wherein said perimeter ofsaid flexible membrane is compressed between said membrane mountingframe and said rear panel.
 7. The vehicle according to claim 1, whereinsaid rear panel comprises a rear mounting panel coupled over at leastone rear door of said vehicle.
 8. The vehicle according to claim 7,further comprising a side wall and a swing panel mounted on an exteriorof said side wall, wherein said swing panel comprises a pair of hingejoints on opposing side edges thereof, wherein a first of said pair ofhinge joints is rotatably mounted to said side wall and a second of saidpair of hinge joints is rotatably mounted to said rear mounting panel.9. The vehicle according to claim 1, wherein said plurality of airchannels is defined internally within said rear panel.
 10. The vehicleaccording to claim 1, further comprising a vacuum pump, wherein saidplurality of air channels is further in fluidic communication betweensaid vacuum pump and said at least one port.
 11. A method for coupling adrag-reducing system to a vehicle, said method comprising: sealing aperimeter of a flexible membrane to a rear panel of the vehicle, whereinthe perimeter encloses at least one port defined in and extendingthrough the rear panel, and wherein the rear panel includes a pluralityof air channels in fluidic communication with the at least one port,each of the plurality of air channels extending parallel to a planedefined by the rear panel; and coupling a pressurization source on thevehicle in fluidic communication with the plurality of air channels. 12.The method according to claim 11, wherein said coupling thepressurization source in fluidic communication with the plurality of airchannels comprises coupling an electrically driven air compressor influidic communication with the plurality of air channels.
 13. The methodaccording to claim 11, wherein the vehicle includes an air-brake system,and wherein said coupling the pressurization source in fluidiccommunication with the plurality of air channels comprises isolatingsaid pressurization source from fluidic communication with the air-brakesystem.
 14. The method according to claim 11, wherein the flexiblemembrane is unitarily formed from a plurality of different resilientlydeformable materials, wherein the plurality of different resilientlydeformable materials each deform differently in response to a givenpressure.
 15. The method according to claim 11, wherein the flexiblemembrane is unitarily formed from a resiliently deformable material andhas portions that each deform differently in response to a givenpressure.
 16. The method according to claim 11, further comprisingcoupling a membrane mounting frame to the rear panel, wherein theperimeter of the flexible membrane is compressed between the membranemounting frame and the rear panel.
 17. The method according to claim 11,further comprising coupling a rear mounting panel over at least one reardoor of said vehicle, wherein the rear mounting panel defines the rearpanel.
 18. The method according to claim 17, further comprising:mounting a swing panel on an exterior of a side wall of the vehicle,wherein the swing panel comprises a pair of hinge joints on opposingside edges thereof, and wherein a first of the pair of hinge joints isrotatably mounted to the side wall; and rotatably coupling the rearmounting panel to a second of the pair of hinge joints.
 19. The methodaccording to claim 11, wherein the plurality of air channels is definedinternally within the rear panel.
 20. The method according to claim 11,further comprising: coupling a vacuum pump to the vehicle; and couplingthe plurality of air channels in fluidic communication between thevacuum pump and the at least one port.
 21. A vehicle comprising: apressurization source; a rear panel; at least one port defined in andextending through said rear panel, said at least one port enclosed bysaid perimeter and in fluidic communication with said pressurizationsource; and a flexible membrane comprising a perimeter, said perimetersealingly coupled to said rear panel, wherein said flexible membranecomprises a unitary flexible membrane formed from a plurality ofdifferent resiliently deformable materials, wherein said plurality ofdifferent resiliently deformable materials each deform differently inresponse to a given pressure.
 22. A method for coupling a drag-reducingsystem to a vehicle, said method comprising: sealing a perimeter of aflexible membrane to a rear panel of the vehicle, wherein the perimeterencloses at least one port defined in and extending through the rearpanel, wherein the flexible membrane is unitarily formed from aplurality of different resiliently deformable materials, wherein theplurality of different resiliently deformable materials each deformdifferently in response to a given pressure; and coupling apressurization source on the vehicle in fluidic communication with theat least one port.